This invention relates to a process for producing alkaline carbonates and more specifically, relates to a process for production of potassium carbonate directly from potassium chloride using a continuous countercurrent cation exchange system. Examples of known commercial techniques for producing potassium carbonate first involve the production of potassium hydroxide. Potassium hydroxide is typically produced using electrolysis of a potassium chloride brine solution. Once potassium hydroxide is produced, it is reacted with a combustion material that generates CO.sub.2 when burned, such as natural gas. During the reaction of potassium hydroxide with CO.sub.2, solid potassium carbonate is produced. Commercial liquid solutions of potassium carbonate may be produced either by dissolving the solids made as above in water, or by introducing carbon dioxide gas into potassium hydroxide made as above.
A drawback to this prior technique is that production of potassium hydroxide requires a large amount of electricity and is energy intensive. Thus, the preparation of the potassium hydroxide is an expensive portion of the procedure. The present invention eliminates the need to first produce potassium hydroxide, thereby eliminating an expensive process step in the current manufacturing scheme.
The present invention also makes substantial technical and economical improvements over earlier cation ion exchange methods described to make potassium carbonate from potassium chloride that are the subject of prior patents, such as U.S. Pat. No. 2,767,057 and Belgium Patent No. 742730. It is not believed that the process to produce potassium carbonate as described in those patents has ever been commercialized, due to inherent limitations on product purity and ion exchange effluent potassium carbonate concentrations which render the previous approaches uneconomic.